Several different methods are presently known to preserve flowers for a long time period, such as those claimed in U.S. Pat. No. 5,252,537 of Oct. 12, 1993, titled “Long-lasting cut flowers and treatment method to obtain them”, filed in the name of Sari Compagnie Du Nord, Inventor Nadine De Winter-Scailteur.
Such U.S. patent divulges a method consisting of replacing the water in the flower tissue by substances inhibiting microorganisms growth. The treatment comprises a dehydration step in which water is drawn out by using an anhydrous solvent, and then is progressively absorbed into the pores of a molecular sieve. Next the solvent is replaced by a mixture of polyethylene glycol, colorants, and the same solvent used in the first step. Finally, the flowers are drained and dried. This procedure gives rise to a product failing to show smoothness and durability required by market users. Additionally, anhydrous solvents used by said method are toxic, thus causing a highly negative environment impact.